The present invention relates to an apparatus for removing foreign matter from the surface of a flexible support.
The term "support" as used herein is intended to mean a flexible belt-shaped support made of plastic film several centimeters to several meters in width, more than several tens of meters in length, and several microns to several hundred of microns in thickness. Examples of the material of the belt include polyethylene terephthalate, polyethylene-2.6-naphthalate, cellulose diacetate, cellulose triacetate, cellulose acetate propionate, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyimide, and polyamide; pieces of paper on which is deposited a layer formed of .alpha.-polyolefins having two ten carbons such as polyethylene, polypropylene and ethylene-butane copolymer; metal foils of aluminum, copper, and tin; and belt-shaped supports which are prepared by preliminarily treating the surfaces of the above-described various belt-shaped supports.
The support is coated with one or more solutions such as a photosensitive solution, magnetic solution, surface protecting solution, charge preventing solution and smoothing solution according to the application. The support thus coated is dried and cut to desired dimensions to provide a desired product. Typical products are various photographic films, pieces of photographic paper and rolls of magnetic tape.
The following methods of removing foreign matter from the surface of such a support are well known in the art. In a first method, a piece of unwoven cloth or a blade is abutted against the support in a suitable manner to remove foreign matter from the support. In a second method, clean air is blown across the belt-shaped support at high speed to remove the foreign matter from the support, and the foreign matter thus removed is directed to a suction hole provided near the support. These methods are of a "dry" type. In contrast to these dry type methods, "wet" type methods are also known in the art. In one of the wet type methods, a belt-shaped support is conveyed into a cleaning solution tank where foreign matter is removed from the support by ultrasonic vibration. In another method, after a cleaning solution is applied to the support, air is blown across the support at high speed (see Japanese Patent Application Publication No. 13020/1974).
These methods all involve particular problems. For instance, the method of removing foreign matter with a piece of cloth or a blade suffers from a difficulty that the support can be scratched by the cloth or blade, or is electrostatically charged by friction. In the case where unwoven cloth is used to remove the foreign matter, fibers of the unwoven cloth may fall onto the surface of the support and stick to the support.
The method of removing foreign matter by applying air at high speed is effective in removing foreign matter of relatively large size, more than about 20 or 30 microns; however it is not effective in removing foreign matter of relatively small size or foreign matter adhering strongly to the support. The wet-type foreign matter removing method described above is disadvantageous in that an apparatus for practicing the method is considerably large in size. Moreover, when foreign matter is removed from a support which is running at high speed, a large quantity of mist is generated which tends to stick not only to the surrounding equipment, but also to the support from which the foreign matter has been removed.
Accordingly, an object of the invention is to provide an apparatus for removing foreign matter from the surface of a support in which the above-mentioned difficulties accompanying a conventional method have been eliminated.